Smartphones and other devices sometimes include miniaturized optoelectronic modules such as light modules, sensors or cameras. Light modules can include a light emitting element such as a light emitting diode (LED), an infra-red (IR) LED, an organic LED (OLED), an infra-red (IR) laser or a vertical cavity surface emitting laser (VCSEL) that emits light through a lens to outside the device. Other modules can include a light detecting element. For example, CMOS and CCD image sensors can be used in primary or front facing cameras. Likewise, proximity sensors and ambient light sensors can include a light sensing element such as a photodiode. The light emitting and light detecting modules as well as cameras can be used in various combinations. Thus, for example, a light module such as a flash module can be used in combination with a camera that has an imaging sensor. Light emitting modules in combination with light detecting modules also can be used for other applications such as gesture recognition or IR illumination.
As illustrated in FIG. 1, one challenge when integrating an optoelectronic module 10 into a device such as a smartphone is how to reduce light leakage 14 from the light source 16 in the light module, or how to prevent incoming stray light from impinging, for example, in the case of sensors or cameras. Preferably, light emitted from light source 16 (or light to be detected by a sensor in the module) should pass through lens 12 and exit (or enter) directly through the transparent cover 18 of the module 10. However, in some cases, some of the light 14 exits (or enters) the sides of transparent cover 18, which can be undesirable.